Abstract: Internal and external magnetic screens made of magnetic permeable material are added between the discharge chamber and the internal and external sources of magnetic field, respectively. A longitudinal gap is maintained between the screens and their respective internal and external poles, that does not exceed half the distance between the internal and external poles. The exit end part of the internal magnetic screen is placed closer to the middle point of the accelerating channel than the internal pole. The walls of the exit end part of the discharge chamber are constructed with an increased thickness, and extend beyond the planes that the poles lay. The magnetic screens can be located with a gap relative to the magnetic path if connected by a bridge between the screens. The discharge chamber, the anode, and the magnetic system are symmetrically designed relative to two mutually perpendicular longitudinal planes.

Abstract: A document security system is described for encoding documents such as credit cards, chargecards and the like with a unique signal representative of the user which cannot be read by the unaided eye and can only be read using a document reading means such as a card swipe machine. In a preferred arrangement the signature of a user is digitized by a digital scanner and compressed and magnetically encoded onto the magnetic stripe of the credit card. The user's portrait can also be digitized and printed on the anti-tamper panel on the card. In use, the user presents the card in a bank or store and the portrait is initially compared with user and assuming there is a likeness, the card is swiped through a card swipe reader and the encoded signature is read and displayed on a LCD-type display. The vendor or teller at the point of use can compare the signature read from the card with the user's actual signature to verify the authenticity of the user.

Abstract: A dispersive laser pulse stretcher and compressor comprises a stretcher portion and a compressor portion. A first mirror, a second mirror, a third mirror, a first grating, a first lens, and a first vertical retroreflector block comprise the stretcher portion. A fourth mirror, a second grating, a horizontal retroreflector, and a second vertical retroreflector block preferably comprise the compressor portion. The input beams for the stretcher and compressor are preferably parallel beams. The present invention also positions the first grating of the stretcher in a parallel plane with the second grating of the compressor.

Abstract: A microwave power divider/combiner (10) comprises a preamplifier (12), a first microwave lens (14), a plurality of amplifiers (16), and a second microwave lens (18). The preamplifier (12) is coupled to receive a microwave source signal (20) and amplify it. The output of the preamplifier (12) feeds the first lens (14). The first lens (14) divides the signal received on its input into a plurality of signals of equal amplitude and phase. Each output of the first lens (14) is then provided to an input of a respective amplifier (16) from the plurality of amplifiers (16). The amplifiers (16) amplify the divided signals and output them to the second lens (18). The second lens (18) has a plurality of inputs and recombines the signals on the inputs into a single higher level signal at an output (22). The present invention also provides a compact configuration for the divider/combiner (10) of the present invention with the lenses (14, 18) mounted on top of each other separated by a mounting block (26).

Abstract: A graphical cursor in text mode is generated by replacing the characters on the display at positions under the cursor with new fonts comprising an image of the cursor superimposed on the image of the characters. The method of the present invention comprises the steps of: determining the new cursor position; restoring the characters at the old cursor position; saving a plurality of the characters near the new cursor position; building new fonts with the plurality of characters near the new cursor position and the cursor symbol; and replacing the plurality of characters at the new cursor position with the new fonts. The preferred method may further comprise the step of detecting the position and movement of the input device when mouse-type input devices are used.

Abstract: A stabilizer for an in situ column drilling apparatus comprises a first and second mounting arms, a first and second stabilizing members, and a first and second stabilizing tabs. The mounting arms are adapted for rotatable coupling to the shaft of column drilling systems. The first and second mounting arms are preferably positioned spaced apart along the shaft near the drilling auger. The mounting arms are coupled together by two stabilizing members at opposite ends of the arms distal the shaft. The stabilizing members are advantageously shaped to fit closely against the wall of the column to prevent changes in the auger's drilling course. The first and second stabilizing tabs are attached to the first and second stabilizing members, respectively. The first and second tabs are mounted to extend radially outward from the shaft and also prevent changes in the auger's drilling course.

Abstract: A dual frequency band antenna (10) having frequency reuse capability. The antenna waveguide (12) includes a four port waveguide network which transmits and receives orthogonal, linearly polarized signals of each of two frequencies. A pyramidal horn (14) is engaged to the mouth of the waveguide, and a meanderline polarizer (16) is engaged to the aperture (17) of the horn (14) to convert the signals from linear polarizations to circular polarizations.

Abstract: A conical TEM power divider/combiner (10) comprises an input port (12), a first circular waveguide (14), a coaxial device (16), a plurality of amplifiers (18), a plurality of cooling fins (20), a second circular waveguide (22), an output port (24), a conical dividing waveguide (42, 32), a first parallel plate waveguide (40, 50), a second parallel plate waveguide (40, 52) and a conical combining waveguide (34, 44). The input port (12) is coupled to the first circular waveguide (14). The first circular waveguide (14) is in turn coupled to the coaxial device (16). The coaxial device (16) divides the signal using the conical dividing waveguide (42, 32), a first parallel plate waveguide (40, 50), and a first plurality of striplines (54). The striplines (54) couple the first parallel plate waveguide (40, 50) to the inputs of the plurality of amplifiers (18). The amplifiers (18) each amplify a respective divided signal and output the result to the second the second parallel plate waveguide (40, 52).

Abstract: A slurry wall lining system comprises a liner and a liner dispenser having a guide, an anchor, a support line, weights and fasteners. The liner dispenser preferably holds a liner in a rolled up position above the trench on rollers for insertion into the trench. The guide is preferably attached to the dispenser and can be angled to extend down into the trench. The liner is unrolled initially in a vertical direction down into the trench at a rate about equal to the movement of the dispenser along the trench. The liner then passes around the guide into a horizontal orientation in the trench. In the preferred embodiment, the weights pull the liner downward about the guide and secure one edge of the liner near the bottom of the trench. The fasteners, support line and anchor to hold the other edge of the liner along the top of the trench.

Abstract: A configurable cellular array is provided having a 2-dimensional array of cells in which each cell in the array has at least one input and output connection at least one bit wide to its neighbours. Each cell also has a programmable routing circuit to permit intercellular connections to be made. In one arrangement each cell contains a programmable function unit which includes a plurality of multiplexers. In a preferred arrangement the function unit and routing unit are programmable using associated Random Access Memory (RAM) areas within the cell. Each cell may be coupled to at least one global or array-crossing-signals so that all cells can be signalled simultaneously. The 2-dimensional array is rectangular and the intercell connections are orthogonal and are one bit wide.

Abstract: An apparatus and method that accurately and reliably detects ice on a target surface (20). Intrinsic birefringent properties of hexagonal ice crystals are used to detect ice by analyzing elliptically-polarized reflection of linearly-polarized radiation from ice. A linearly-polarized radiation beam (15) is focused on the target surface (20), and returned radiation (25) is filtered (30) as a function of its elliptical polarization. Filtered radiation (35) is directed to a sensor (40) and quantified according to the intensity of radiation received at various points (41.sub.1 -41.sub.n) on the filter (30), and an output signal for each point is produced (45.sub.1 -45.sub.n). The presence or formation of ice is determined by a signal processor (50) that detects the variance among the output signals (45.sub.1 -45.sub.n)--a variance (55) reaching a threshold value being indicative of ice.

Abstract: A pipelined random access memory for use in color display system. A multiplexer, including a video port and a microprocessor port, provides the RAM input. A memory array, a sensing latch and an I/O latch, in addition to the multiplexer, provide the pipeline architecture, enabling the random memory to be accessed at three different locations simultaneously. Thus, with the same memory speed, the data throughput of this RAM is triple that in the known art. A clock circuit is constructed to generate extremely stable internal clock pulses so that the interval of each clock pulse varies automatically according to the IC manufacturing process and the ambient temperature in use, thereby adapting to the appropriate precharging interval related to the memory array, multiplexer, and sensing latch.

Abstract: A communication system comprising a wireless keyboard for emitting infra-red signals, a receiving unit for converting the infra-red signals to an electrical signal, a tuning and amplifying circuit coupled to the receiving unit for tuning and amplifying the electrical signals, a carrier filtering circuit for removing the carrier component of the input signal, a single-shot circuit coupled to the carrier filtering circuit for converting its input signal to a known code wave form, and a microprocessor for receiving the code wave. The invention allows multiple users to operate their wireless keyboards without interference.

Abstract: A high speed digital counter that can be easily tested comprises a plurality of subcounters having an input for receiving an incrementing signal and a carry output for outputting a carry signal when the subcounter has reached its counting capacity. The carry output of each subcounter is gated to the input of a next more significant subcounter by an OR gate which receives as inputs the carry signal and a test signal. The OR gate performs an OR on these two signals and outputs the result to the input of the next more significant subcounter. The OR gate allows the test signal to access each subcounter separately, and thus, each subcounter may be tested individually.

Abstract: A printer buffer system for connecting a number of personal computers and a number of printers includes a master printer buffer and one or more slave buffers, forming an expandable printer buffer system. Each buffer includes an input storage device for storing data, command and status signals from a personal computer or for controlling the transfer of data between the computer and the buffer as well as output storage devices for storing status, command and data signals for the transfer of data between the printer and the buffer and for controlling such transfer. Personal computers and printers may be added or removed from the system at will and the user may select a designated printer.

Abstract: A method for making a battery electrode includes roughening the surface of a substrate (10) that constitutes a precursor to the electrode, using an electrolytic solution (12) with electrical potential perturbations applied thereto. The substrate (10) of porous sintered nickel powder is first formed. The electrolytic solution (12) prefereably contains the pure metal that forms the electrode. Then all gases in and around the substrate (10) are preferably removed. Next, the substrate (10) is placed in the solution (12) for a predetermined amount of time. Potential perturbations are then applied to the substrate (10) and the solution (12). The potential peturbations vary between the voltages necessary for electrodissolution and electrodepositon of the substrate (10), and thus, cause the surface of the substrate (10) to be roughened as portions of the substrate (10) are dissolved into the solution (12) and then redeposited onto the substrate's (10) surface.

Abstract: A nine bit Gray code counter is constructed as a single integrated circuit such as a PLA and comprises D flip-flops, AND gates and Exclusive-OR gates. The array is programmed to provide a nine bit Gray code count at its outputs. The Q output of each flip-flop provides one bit in the Gray code count. The D input to each flip-flop is determined by the significance of the bit and the following equations: D0=A XOR Q0; D1=(A.multidot.Q0) XOR Q1; Dn=(A.multidot. . . . .multidot.Qn-2.multidot.Qn--1) XOR Qn; and Dmsb=(A.multidot.Q0.multidot.Q1.multidot. . . . .multidot.Qmsb-2 XOR Qmsb.

Abstract: A clock switching circuit comprises a multiplexer, a gate, a first detector, a second detector and a state machine. The multiplexer receives two clock signals and outputs one of them through the gate. The first detector is coupled to the output of the multiplexer and the second detector is coupled to the output of the gate. The state machine controls the output of the gate and the multiplexer in response to signals from the first and second detector, and prevent glitches from being output by the gate.

Abstract: In a battery powered data processing system having an oscillator and a microprocessor connected to the oscillator, the microprocessor has a programmable standby mode and circuit responsive to the standby mode for disabling the oscillator. The system uses a sensor circuit to generate a reset signal to reset the microprocessor from the power down mode when a key is depressed. A signal generator is responsive to signals from the oscillator for disabling the reset signal.

Abstract: A computer keyboard interface is disclosed with an improved system for controlling the signals on a clock line and a data line for communication between the keyboard interface and the system interface. Two bi-directional input/output ports are used, one for the clock line and one for the data line. The data and clock lines are then used not only for the transmission of data but also used by the keyboard interface for sensing status signals from the system interface. This simplifies the keyboard interface design.